HTTP/LDAP/SMTP/IMAP/POP/DNS/DHCP HOWTO

This web page provides all the commands required to setup a HTTP,
LDAP, SMTP, IMAP, POP, DNS and DHCP server. The emacs commands mean
you are required to edit this file. Acquiring example files is
discussed at the bottom of this page. The following should work for
most flavors of Ubuntu (last updated for 10.10).
The package names may have changed somewhat.

Network Router Config

If your server is connected to the internet via a router, you will
need your router to forward incomming traffic on port 25 (SMTP), port 143
(IMAP), port 80 (HTTP) to your server. This can be done via the
following script:

Machine Optimization

svctm (via iostat) should be no greater then 30
(milliseconds) and %util (via iostat) should be no greater
then 5 (%). This indicates the system disk(s) are not tuned or are
too slow.

%wa (via top) should be no greater then 30 (%). This
indicates the system disk(s) are not tuned or are too slow.

procs r (via vmstat) should be no greater then the
number of CPUs on the system and no more then four times the number of
available CPUs on the system. This indicates shortage of CPU
power.

cpu sy (via vmstat) should be no greater then four
times cpu us (via vmstat). This indicates shortage of CPU
power.

Once you have determined a machine is in overload (e.g. your
server is using to much cpu, memory or disk read/write access). Then
you can either upgrade the cpu, memory or disk speed. However if disk
speed is your problem (a common problem, see above) due to, for
example, mysql, you could even the load via moving your
/var/lib/mysql/ directory to a second drive or another machine.